A PIN diode is a semiconductor diode with a lightly doped intrinsic semiconductor region in a substrate between a p-type region and an n-type region. When radiation or charged particles of sufficient energy impact the intrinsic region, an electron-hole pair is created that generates current between the p-type and n-type regions. The PIN diode can be used to detect photons as well as various types of charged particles including alpha particles and beta particles in a variety of sensors, such as radon sensors, radiation sensors, light sensors, and smoke detectors, among others. One difficulty with using PIN diodes for sensors is the lack of sensitivity to detect indirectly ionizing neutrons because the impact of a neutron in the intrinsic region does not directly generate current as neutrons are electrically neutral. Additionally, the usefulness of a sensor is often proportional to the sensitivity of the PIN diode. It is therefore desirable to provide PIN diodes with enhanced levels of sensitivity, and with the ability to detect neutrons in addition to charged particles and photons.